Cities A, B and C are located on a straight road. The car drove from A to B for 4 hours, from B to C for 3 hours

Cities A, B and C are located on a straight road. The car drove from A to B for 4 hours, from B to C for 3 hours, increasing the speed by 20 km / h. From C to A (through B), he returned within 9 hours, and his speed was 10 km / h less than on the way from A to B. At what speed did the car go from A to B and what is the distance from A to C ?

Let’s denote by x the speed of the car in km / h on the section from A to B.
The speed of the car on the aircraft section will be (x + 20) km / h;
The speed of the car on the CBA section is (x – 10) km / h.
Let’s make the equation:
4 * x + 3 * (x + 20) = 9 * (x – 10);
7 * x + 60 = 9 * x – 90;
2 * x = 150;
x = 75km / h.
Distance between A and C: 9 * (75 – 10) = 585 km.